The present invention relates to a ground-fault circuit interrupter.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Ground-fault circuit interrupters are provided for the purpose of triggering in the case of the occurrence of a fault current of a specific level and disconnecting an electrical subnetwork from a power supply network in this way. Various aging procedures, such as change or worsening of the magnetic properties of a summation current transformer, can have the result that the fault current required for triggering the ground-fault circuit interrupter rises over time. This typically remains unnoticed by a user for a long time. The user does have the possibility of monitoring the function of the ground-fault circuit interrupter using the test unit, however, a simulated test fault current is typically generated by such a test unit, or at least in the case of typical ground-fault circuit interrupters which are independent of the network voltage, the test fault current being significantly higher than the rated fault current of the relevant ground-fault circuit interrupter. Therefore, the correct functioning in case of fault cannot be concluded from a successful test of a ground-fault circuit interrupter. In addition, in the typical test unit, in particular in the case of ground-fault circuit interrupters independent of the network voltage, the level of the actually generated test fault current is a function of the currently applied network voltage, which is naturally subject to certain unpredictable variations. “Old” ground-fault circuit interrupters therefore possibly represent a hazard to living beings and facilities, it currently not being able to be established by a user whether a specific installed ground-fault circuit interrupter still offers protection.
It would therefore be desirable and advantageous to obviate prior art shortcomings by providing an improved ground-fault circuit interrupter, wherein the functional reliability can be checked more precisely, in particular independently of the network voltage.